A method of this type is generally known. In the known method, the distance between the metal strip and the anode is usually held at between 5 and 10 cm, while the strip which is to be coated, in the transverse direction in the vicinity of the anode, usually extends over a multiple (usually approximately 1 m) of this distance, with the result that a relatively narrow clearance is formed between the metal strip and the anode. A potential difference is applied between the anode and the cathode, leading to an electric current flowing through the electrolyte. In a method in which soluble anodes are used, the electric current leads to the dissolution of material, usually one or more metallic elements, from an anode, on the one hand, and the precipitation of the said material in a layer on the strip, on the other hand.
It is usually aimed to apply the layer at the highest possible speed. The rate at which the layer grows is dependent, inter alia, on the electric current density and on the velocity at which the strip is moved through the electrolyte. However, the electric current density affects not only the growth rate of the layer but also its morphology. Since undesirable dendrites are formed above a set threshold, the maximum current density is in practice limited.
The velocity of the strip is also limited in practice. If the strip velocity were too high, given a specific, more or less limited growth rate, the coating line would become too long for a specific desired layer thickness to be reached.
It is known to use special jets on either side of the strip to spray the electrolyte into the clearance between the strip and the anode substantially in the transverse direction with respect to the direction of movement of the strip. In this way, the flow velocity of the electrolyte through the clearance is increased.
One drawback of the known method is that the flow of the electrolyte in the clearance is not sufficiently uniform, with the result that the morphology and thickness of the deposited layer are not sufficiently uniform. Yet another drawback is that the known jets are complicated and are expensive to maintain and operate.